Apparatus for producing polyurethane foam

ABSTRACT

Apparatus for producing continuous polymeric foam slabs or strands, characterized in that the liquid foam reactants are initially introduced into the bottom of a vessel and the resulting foam is allowed to expand upwardly in the vessel owing to chemical reaction between the reactants. Prior to completion of the expansion of the foam mixture, the partially expanded foam is allowed to flow from the vessel over a weir structure, whereupon the foam completes the expansion process in a channelshaped conveyor in which the foam is continuously moved away from the weir structure. According to one embodiment, the foam that flows over the weir moves down an inclined fall plate surface during completion of the foam expansion. In another embodiment, the expanding foam passes over the weir directly onto the horizontal reach of a conveyor.

United States Patent [191 Berg Aug. 27, 1974 APPARATUS FOR PRODUCINGPOLYURETHANE FOAM Primary Examiner-R. Spencer Annear AssistantExaminer-Mark Rosenbaum [75] Inventor Laader Berg splelkavlk NorwayAttorney, Agent, or Firm-Lawrence E. Laubscher [73] Assignee: UniformAG, Glarus, Switzerland [22] Filed: May 22, 1973 [57] ABSTRACT [62]Division of Ser. No. 174,412, Aug. 24, 1971, Pat. No.

[52] US. Cl. 425/4 C, 264/47, 425/115,

425/224, 425/329, 425/817 C [51] Int. Cl B2911 27/00 [58] Field ofSearch 425/4 C, 112, 817 C, 371, 425/150, 471, 115, 329, 364, 224;264/47 [5 6] References Cited UNITED STATES PATENTS 3,042,988 7/1962Goransson et a1. 425/817 X 3,123,856 3/1964 Dye et a]. 264/47 X3,152,361 10/1964 Edwards 425/224 X 3,152,363 10/1964 O'Connor Honey eta1. 425/364 3,488,800 1/1970 Kornylak 425/115 Appl. No.: 362,839

Related US. Application Data Apparatus for producing continuouspolymeric foam slabs or strands, characterized in that the liquid foamreactants are initially introduced into the bottom of a vessel and theresulting foam is allowed to expand upwardly in the vessel owing tochemical reaction between the reactants. Prior to completion of theexpansion of the foam mixture, the partially expanded foam is allowed toflow from the vessel over a weir structure, whereupon the foam completesthe expansion process in a channel-shaped conveyor in which the foam iscontinuously moved away from the weir structure. According to oneembodiment, the foam that flows over the weir moves down an inclinedfall plate surface during completion of the foam; expansion. In anotherembodiment, the expanding foam passes over the weir directly onto thehorizontal reach of a conveyor.

20 Clains, 12 Drawing Figures m-aaoss PAYENTEBAUGZTIHM SHEET 3 OF 6PATENIEB 1x02271974 SHEEI 6 [IF 6 APlARATUS FOR PRODUCING POLYURETHANEFOAM This is a divisional application of application Ser. No. 174,412filed Aug. 24, 1971, now Pat. No. 3,786,122.

This invention relates to the continuous production of polymeric foamstrands, e.g. continuous strands of polyurethane foam.

In such production it is common practice to deposit a mixture of liquidfoam reactants onto the bottom of a continuous channel-shaped conveyorand allow the foam to rise freely due to chemical reaction until astrand of fully-expanded foam is obtained. The foam strand is thenallowed to cure and, subsequently, is cross-sawn into blocks foreventual conversion into, for example, mattresses or cushions.Typically, an apparatus for such production is 50 metres long andproduces a continuous foam strand having a cross-section of, say, 2metres wide and 80 centimetres high.

The channelshaped conveyor is usually formed from a sheet or sheets ofpaper arranged to constitute the bottom and two vertical sides of thechannel, the bottom moving on and with a belt conveyor and the sidessliding past rigid retaining walls or being supported by movingretaining walls which move with the belt conveyor. Foam reactants aremixed in a mixing head and fed through a nozzle, the head and nozzlebeing reciprocated across the upstream end of the trough conveyor in amanner such that the mixture of liquid reactants is deposited evenly onthe bottom of the conveyor.

Due to the substantial size of such apparatus, particularly the length,large factory premises are required. Additionally, ample head room isnecessary to accommodate the receiprocating mixing head and nozzle.

Such known production method and apparatus give rise to a number ofproblems and disadvantages. The mechanism for reciprocating the mixinghead and nozzle is inevitably complicated and expensive. As the mixtureof foam reactants passes along the channel conveyor, evaporation ofgases and absorption of reactants by the channel papers occurs,resulting in substantial loss of reactants, particularly in the initialstages of foaming whenthe reactants are more liquid than solid.Furthermore, the top surface of the foam tends to take a convex shapedue to friction or adhesion between the rising foam and the channelsides, so that subsequent conversion of the resultant foam blocks isless economic than with equivalent rectarigular-sectioned blocks.

The considerable length necessary for such apparatus is inconvenient.The stages of production along the conveyor are (a) depositing themixture of foam reactants on the trough conveyor, (b) allowing thereactants to foam freely until expansion ceases, allowing the expandedfoam to cure, during which stage the paper sheet or sheets constitutingthe channel are usually removed, and (d) cross-cutting the cured foamstrand into blocks of required size.

The speed of the conveyor is determined by factors relating to the firstand second stages. The mixture of reactants is a liquid of low viscositywhich is distributed evenly across the conveyor beneath thereciprocating nozzle and it is important that this even distributionshould be maintained as the liquid moves with the conveyor and starts tofoam. Flow of the liquid back against the conveying direction must beavoided by choice of a sufficiently fast conveyor speed. It is alsocommon practice to assist in avoiding such back-flow by inclining theconveyor downwardly in the conveying direction. However, the speed ofthe conveyor must not be so fast and the conveyor inclination must notbe so great as to cause the liquid to flow excessively in the conveyingdirection and flow under previously deposited liquid which has startedto foam. (In a typical example the inclination of the conveyor would be45 to the horizontal and the conveyor speed would be 5 metres perminute). Failure to ensure that the even distribution of liquid ismaintained will result in an unacceptable product-which is not uniformin density,is misshapen, or which exhibits splits and tears in the foamstructure. I

Such factors dictate a certain minimum conveyor speed through the firstproduction stage and it follows that the total length of the conveyormust travel at the same speed.

Another consideration relates to the height of the resultant foamblocks. This should be as high as possible, for a given width of block,in order to increase the proportion of usable foam to block skin (whichusually must be removed). If all other parameters were equal, the heightof the fully expanded foam would be dependent on the conveyor speedthrough the second, foaming, stage of production, so that the conveyorspeed through this stage should be as low as possible to achieve maximumfoam height. Furthermore, the curing process in the third stage proceedsas a function of time and is not affected by conveyor speed. The fasterthe conveyor speed, the longer must the third stage be in order that thenecessary curing time shall elapse as the foam progresses through thatstage. As this curing stage occupies a substantial part of the conveyorlength, the result is an inconveniently long conveyor;

- for example 50 metres long.

Among the objects of the present invention are the provision of a methodand apparatus for the production of a continuous strand of polymericfoam in which the need for a reciprocating mixing head and nozzle iseliminated.

Another object is the provision of such method and apparatus whichenables a conveyor to be employed which is considerably shorter inlength than the conveyor required in previous proposals.

A further object is the provision-of such method and apparatus whichenables the conveyor to be run through the foaming stage at a speedslower than that required in previousproposals.

Another object of the invention is to enable such a foam strand to beproduced having a substantially flat upper surface.

According to one feature of the invention, a method I of producing acontinuous strand of polymeric foam from a mixture of liquid foamreactants, in which expanded foam is formed in a continuously-movingchannel-shaped conveyor, comprises the steps of continuously supplying amixture of liquid foam reactants to the bottom of a vessel, allowing themixture to expand upwardly in said vessel due to chemical reactionbetween said reactants, prior to completion of expansion of the mixtureallowing partially-expanded foam to flow from said vessel over a weirstructure, and thereafter allowing the foam to complete the expansionprocess in a channel-shaped conveyor in which the foam is continuouslymoved away from said weir structure.

According to another feature of the invention, apparatus for carryingout the above-stated method comprises a vessel in which liquid foamreactants may expand upwardly, means for supplying liquid foam reactantsto the bottom of said vessel, a weir structure associate with saidvessel so that foam rising by expansion in said vessel will flow oversaid weir structure, and a channel-shaped conveyor associated with saidweir structure and arranged continuously to convey foam away from saidweir structure.

Further features and objects of the invention will become apparent fromthe following description of various embodiments, given by way ofexample only, with reference to the accompanying drawings, in which:

FIG. I is a diagrammatic vertical crosssection taken along the length ofone embodiment of apparatus according to the invention;

FIG. 2 is a plan view of the apparatus of FIG. 1, prior to theintroduction of foam reactants;

F IG. 3 is a diagrammatic representation of apparatus similar to thatseen in FIG. 1 and indicating various adjustment features;

FIG. 3a is a diagrammatic representation of details of FIG. 3;

FIG. 4 is a plan view of part of the apparatus shown in FIG. 3 andincorporating further adjustment features;

FIG. 5a shows a part of the apparatus shown in FIG. 1, including amodification;

FIGS. 5b and 50 show elevation and plan views respectively of themodification shown in FIG. 5a;

FIG. 6a is similar to FIG. 5a, but including an alterna-' tivemodification;

FIG. 6b shows a plan view of the modification shown in FIG. 6a;

FIG. 7 is similar to FIG. 1 and shows another embodiment of apparatusaccording to the invention; and

FIG. 8 is a perspective view, with parts shown broken away, of a furtherembodiment of apparatus according to the invention.

Referring to the drawings, the embodiment of the invention shown inFIGS. 1 and 2 comprises a stationary mixing head 10, the output of whichis connected by piping 11 to a vessel in the form of a trough 12. A beltconveyor 13 has its conveying reach arranged to move horizontally in thedirection of arrow 14, over a stationary supporting platform 15. Betweenthe conveyor 13 and the trough 12 are arranged an inclined fall plate 16and an upright support member 17 having minimal spacing from a lip 18 ofthe trough 12. A sheet of material 19, for example kraft paper, from asupply roll 20 passes upwardly over the member 17 between said memberand the trough lip 18, around a roller 21, over the inclined surface ofthe fall plate 16, and onto the conveying reach of the conveyor 13 tomove thereafter with said conveyor.

Contiguous with each edge of the sheet 19 is a vertical side sheet 22,of material which also may be kraft paper, drawn from a respectivesupply roll 23, by means not shown, in the conveying direction of arrow14 and at the same speed as the conveyor 13. The side sheets 22 aresupported by respective rigid side walls 24 and constitute, with thebottom sheet 19, an opentopped channel conveyor.

The trough 12 comprises an upright rear wall 25 and side walls 26 of thesame height. The front wall 27 of the trough is inclined to rise from abase 28 of the trough to the trough lip 18. The piping 11 is connectedto the trough adjacent the base 28. As seen in FIG. 2, the lower part ofthe trough is divided into sections by baffle plates 29 and each sectionis fed by a branch pipe 11a from the mixing head 10, the pipingarrangement being such that each trough section receives mixture fromthe head 10 which is the same age (i.e. has travelled the same distance)as that received by all the other sections. Instead of the arrangementof baffle plates 29, as shown, baffle plates can extend along the lengthof the trough (i.e. at right angles to the plates 29) the plates beingspaced from each other across the trough width. Such plates can also bespaced from the bottom of the trough. Alternatively, instead of baffleplates, a perforated false floor can be provided across the troughlocated just above the inlets from pipes 110.

In operation, the mixing head 10 is fed with chemical reactants suitablefor producing polymeric foam, as known per se. The mixture of reactantsis fed through the piping 11 to the respective sections of the trough12. The mixture of reactants is initially liquid as it arrives in thetrough but, as the liquid level rises, the mixture begins to expand andfoam in manner known per se, due to chemical reaction. The expandingfoam rises upwardly in the trough, passing the lip 18 and contacting themoving sheet 19. The foam continues to rise upwardly until it arrives atthe region where the sheet 19 turns over the roller 21 and moves downover the fall plate 16. The roller 21 and the region of the sheet 19overlying the roller constitute a weir structure 30 over which the foamflows, the foam being in a condition in which it is changing from amainly-liquid to a mainlysolid state. As the foam expands and rises inthe trough 12 so fresh liquid mixture is supplied to the bottom of thetrough. Thus, a constant flow of solidifying foam passes over the weir30 and moves down the incline of the fall plate 16. The angle ofinclination of the fall plate 16 with the horizontal is chosen such thatthe foam, continuing to expand, retains a horizontal top surface 31.Also the arrangement is such that when the foam reaches the bottom ofthe fall plate, expansion or foaming has substantially ceased and theexpanded foam continues horizontally along the conveyor while foamcuring takes place.

By the time the expanding foam, in the trough 12, reaches the weir 30 ithas acquired'a sufiicient viscosity that it does not seep between theedges of the sheet 19 and the side sheets 22. Furthermore, as the foampasses over the weir 30, the viscosity is such that the foam movesdownwardly with the sheet 19 and exhibits negligible tendency to flowinadvance of the sheet 19.

EXAMPLE Using an apparatus as described with reference to FIGS. 1 and 2,a mixture of liquid polymeric foam reactants was produced in the mixinghead 10, constituted as follows:

Parts by Weight Polyether Triol (Polypropylene Glycol) (Union CarbidePolyol -Continued Parts by Weight Water 3.20 Triethylene Diamine (DABCO)0.10 Silicone Surfactant (Union Carbide L-540) L50 StannousOctoate-Catalyst (T-9) 0.20 Tolyene di-Isocyanate (Index l) 42.00

This mixture was fed to the trough 12, the baffles 29 preventing undueturbulence of the liquid. As the upper level of the liquid expandedupwardly, the expanding foam formed a seal over new liquid arriving inthe trough, thereby reducing loss of gas evolved from the liquidreactants. Partially expanded foam was allowed to flow over the weir 30at which stage the foam came into contact with side sheets 22. Due tothe viscosity of the foam it did not seep between the bottom sheet 19and the side sheets 22. As the expanding foam passed with the sheet 19down over the fall plate 16, the further foam expansion was compensatedby the downward gradient of the fall plate, so that the resultant foamstrand was produced with a flat top surface. After expansion had ceased,the foam strand was allowed to cure as it continued along the horizontalconveyor.

The speed of the conveyor 13, and thus the sheets 19 and 22, was 3metres per minute. The overall length of the apparatus was about 13metres and the distance between the side sheets 22, i.e. the width ofthe resultant foam strand, was 2 metres. The foam strand was 1 metrehigh and had a substantially flat top surface, as seen in cross-section.The sides of the strand-were substantially flat and, after a block hadbeen cut from the strand and converted, the skin of the block was foundto be less dense than that produced by previouslyproposed processes. Ingeneral, the foam block was of excellent structure and surface shape andhad a substantially uniform density throughout the volume containedwithin the skin regions.

It was also noted that the absorption of foam reactants by the sheets 19and 22 was much lower than experienced with previously-proposedprocesses, due to the fact that the foam does not contact said sheetsuntil the foam has expanded beyond the mainly-liquid state.

The primary advantage of the method and apparatus of the invention isthat the mixture of foam reactants is not brought into contact with themoving sheets 19 and 22 untilthe mixture has commenced to foam. Themixture is contained, in the wholly-liquid state, in the bottom of thetrough l2 and thus the problems associated with liquid flow (experiencedwith previous methods and apparatus) do not arise. The foam does notcome into contact with the conveyed sheets until it has expanded beyondthe wholly-liquid state and, therefore, the conveyor and the sheets 19and 22 can be transported at a much lower speed than hitherto withoutlosing control of the foam. Thus, the final stages of expansion and thesubsequent curing of the foam can take place on a relatively slow-movingconveyor and, therefore, in a greatly reduced conveyor length.

In order to achieve maximum height of the resultant foam strand and alsoa cross-section which is as near as possible rectangular, it may bedesirable to provide for ready adjustment of one or more dimensions orelements of the apparatus. Referring to FIG. 3, the apparatusdiagrammatically represented is similar to that described with referenceto FIGS. 1 and 2. A trough 40 can be fed with liquid foam reactantsthrough a pipe 41 in a back plate 42. The base 43 of the trough isrelatively wider than that of FIG. 1 and the front plate 44 extendsupwardly to an extended lip 45 in the weir region 46. The lip 45overlies a roller 47 for entraining the sheet 19 from the supply roll20.

The fall plate is constituted by a number of parts comprising a curvedsupport plate 48 mounted for piv otal movement about the axis of theroller 47. The free end of plate 48 overlies the upper end of a flexiblesupport plate 49, the lower end of which overlies a wedge structure 50which, in turn, overlies the conveyor 13. The sheet 9 is passed aroundthe roller 47 and down the fall plate to the conveying reach of theconveyor 13.

The shape and attitude of the fall plate is adjustable through a widerange, by virtue of adjustment facilities provided at different parts ofthe apparatus. The trough 40 can be raised'to a limiting position 40a bya ram 51, the roller 47 moving with the trough to a position 47a. Thewedge structure 50 is movable to a retracted position 50a by a motor 52which activates a screw drive 53. The shape and attitude of the flexiblesupport plate 49 are adjusted by three hydraulic cylinders 54, and 56,the pistons of which are attached to respective points spaced along thelength of the plate. For the sake of clarity in FIG. 3, the points ofattachment of the cylinders themselves are indicated in FIG. 3a.Cylinders S4 and 55 are attached to the apparatus framework 57. A linkmember 58 is pivotally attached at one end to the point 59 on plate 49where the piston of cylinder 54 is attached. The piston of cylinder 55is not attached directly to the plate 49 but via the intervening end ofmember 58. Cylinder 56 is attached to the member 58. Actuation ofcylinder 54 positions point 59 of the plate 49 along a path indicated bythe chain line 54a. Actuation of cylinder 55 positions the end of member58, and therefore the corresponding point on plate 49, along an arcuatepath (about point 59) indicated by the chain line 55a. Actuation ofcylinder 56 deflects the relevant section of plate 49 between a convexcontour indicated by chain line 49a and a concave contour indicated bychain line 49b.

By a suitable combination of adjustments, variations in foam behaviourdue to different foam formulations and changes in ambient conditions canbe compensated so that a satisfactory resultant product is obtained. Forexample, a foam formulation exhibiting a high rate of foam rise can beaccepted by elevating the trough to position 40a and retracting thewedge structure to position 501;, thereby increasing the angle of thefall plate so that the bottom sheet 19 follows a path 190.

It is intended that all the aforementioned adjustments should becontinuous between the indicated limiting conditions. Furthermore, it isenvisaged that only selected ones of the described adjustments will beprovided in certain cases. In particular, a sufficient degree of foamcontrol might be achieved by incorporating only the adjustable wedge 50,the fall plate being wholly constituted as an extension of the supportplate 48, in order to provide a limited range of adjustment of the fallplate angle.

Control of the top surface shape of the expanded foam can be achieved bycontrolling the amount of foam flowing over the weir at different pointsalong the weir; in particular causing more or less foam to flow at theend portions of the weir than at the central portion. In FIG. 4, thetrough of FIG. 3 is seen in plan and the back plate 42 is deformablebetween positions 42a and 42b by an hydraulic cylinder 60. When theplate is in the position 42a more foam will flow over the ends of theweir than at the centre and vice-versa when the plate is in the position42b. If desired, additional hydraulic cylinders 61 can be employed toprovide improved control of the back plate deflection.

Where the need to depart from a uniform flow over the weir can bepredetermined with sufficient accuracy, a boom can be provided along theedge of the weir, as shown in FIGS. 5a to 5c. The trough 64 seen in FIG.5a is similar to that of FIG. 1, except that the front lip is extendedupwardly at 65 to the level of the weir and carries along its upper edgea boom 66, the foam having to flow over the boom to thedownwardlyinclined bottom sheet 19. The boom is shaped at its ends toallow more foam to flow over the ends than at the centre. As seen inelevation (FIG. 5b) and in plan (FIG. 5c) the ends 660 of the boom aretapered to permit less restricted flow of foam at the ends of the boomthan elsewhere along the boom.

An alternative device for controlling the amount of foam flowing fromdifferent points along the weir is shown in FIGS. 6a and 6b, in whichthe extended front lip 65 of the trough has attached to it an apron 67which extends downwardly over the bottom sheet 19. The shape of theapron, in plan, is seen in FIG. 6b. The apron is formed of siliconisedpaper so that foam flowing over the apron experiences a frictional dragrelative to the apron surface. Thus, in view of the apron shape, foamflows onto the bottom sheet 19 faster from the ends of the weir thanfrom the central portion.

In applications in which the expanded foam product is required to berestricted in height, say up to a maximum of about 5 cms. high,advantages of the invention can be obtained without employing a fallplate. FIG. 7 shows an apparatus similar in many respects to that shownin FIG. 1 and like parts are denoted by the same reference numerals asin FIG. 1. However, after the bottom sheet 19 is directed upwardly pastthe trough lip 18, the sheet passes directly onto the conveying reach 70of a belt conveyor 71 (corresponding to the conveyor 13 of FIG. 1). Theconveying reach 70 moves horizontally in the direction of the arrow 72and the weir 30 is constituted at the upstream end 73 of the conveyor.If desired, the lip 18 of the trough can be modified so as toincorporate the flow control devices described with reference to FIGS.5a to Sc and FIGS. 6a and 6b. Furthermore, the trough shape can beadjustable as described with reference to FIG. 4.

The embodiment of FIG. 7 has particular application to the production offoam-backed sheet material, the bottom sheet 19 then being constitutedby the material to be backed. The sheet 19 might be of a textilematerial, possibly with that surface which will contact the foam beingtreated to assist adhesion of the foam to the sheet. As the sheet 19 istransported upwardly past the trough lip 18, it will contact expandingfoam which is sufficiently tacky to adhere satisfactorily to the sheetbut which is no longer wholly liquid so as to be absorbed excessively bythe sheet material. Such excessive absorption is an acknowledged problemin previously-proposed production methods.

Some of the advantages of the present invention can be obtained usingconventional apparatus for the continuous production of polymeric foamstrands, with a relatively simple modification. Referring to FIG. 8,such conventional apparatus comprises an opentopped channel conveyorconstituted by paper side sheets 80, supported by rigid stationary sidewalls 81, and a paper bottom sheet 82 supported by a conveyor belt (notshown) which transports the channel conveyor in the direction of arrow83. A mixture of liquid foam reactants is deposited on the bottom sheet82 through a feed nozzle (not shown) reciprocated across the conveyor atthe upstream end thereof and the foam reactants expand as the conveyormoves along. Such conventional apparatus is very well known so as not torequire further description.

The modification according to the present invention involves maintainingthe feed nozzle stationary and connecting it to a pipe 84 leading to atrough 85 extending across the width of the channel conveyor andsupported, with minimal clearance, above the bottom sheet 82. The troughmay be fashioned from sheet metal and comprises a front wall 86extending upwardly to a lip 87 leading to a downwardly inclined fallplate 88. A baffle plate 89 divides the lower part of the trough intotwo sections each connected to the pipe 84 through a respective branchpipe 90.

In this embodiment the trough lip 87 constitutes the weir and liquidfoam reactants fed to the bottom of the trough begin to expand and riseuntil they flow over the weir (the lip 87) and pass down the fall plate88 onto the bottom sheet 82 of the channel conveyor. Thus, evendistribution of liquid foam reactants can be achieved without employingany reciprocating or otherwise moving nozzle. Furthermore, expandingfoam is deposited on the bottom sheet 82 of the channel conveyor, ratherthan liquid reactants, and such foam will tend to retain its intendedposition on the conveyor so that the conveyor can be run at a lowerspeed than usual.

Due to the non-adjustable nature of the structure of the trough 85, itmay be found that certain formulations of foam reactants do not achievea sufficiently solid state before flowing onto the channel conveyor.This problem can be overcome by providing, as shown, a rectangular apron91 attached at 92 to the base of the trough 85 and extending downstreaman appropriate distance from the fall plate 88. The apron overlies thebottom sheet 82 of the channel conveyor and is formed of a sheet ofsiliconised paper. Friction between the foam and the apron retards theflow of the foam to allow a greater degree of foam expansion before itreaches the bottom sheet 82 of the conveyor. If desired, thedistribution of foam across the channel conveyor can be controlled byshaping theedge of the apron as indicated by the broken line 91a and asexplainedwith reference to FIGS. 6a and 6b.

We claim:

1. Apparatus for producing a continuous strand of polymeric foam from amixture of liquid foam reactants, which comprises a. a vessel in whichliquid foam reactants may expand upwardly;

b. means for supplying liquid foam reactants to the bottom of saidvessel;

c. weir means so arranged adjacent the upper portion of said vessel thatthe foam which rises by expan-- sion in said vessel flows over said weirmeans; and

d. open-topped channel-shaped conveyor means for conveying foam awayfrom said weir means.

2. Apparatus as defined in claim 1, wherein said vessel comprises atrough having a length dimension in a direction parallel with said weirmeans which corresponds with the width of the foam strand to beproduced.

3. Apparatus as defined in claim 2, wherein the width of said troughincreases with trough height.

4. Apparatus as defined in claim 1, and including at least one baffleplate arranged in the lower part of the trough for dividing the troughinto a plurality of sectrons.

5. Apparatus as defined in claim 4, wherein said reactant supplyingmeans is operable to supply reactants separately and simultaneously toeach of said trough sections.

6. Apparatus as defined in claim 1, and further including means foradjusting the horizontal crosssectional configuration of said vessel.

7. Apparatus as defined in claim l, wherein said conveyor meanscomprises a pair of parallel spaced vertical side wall sheets and abottom wall sheet arranged to define a channel configuration, each ofsaid side and bottom wall sheets being supplied from a separate supplyroll, respectively.

8. Apparatus as defined in claim 7, wherein said conveyor means furtherincludes an endless belt conveyor the conveying reach of which moves ina direction away from said vessel in supporting engagement with saidbottom sheet, said bottom sheet being drawn from its supply rollupwardly past said vessel by said belt conveyor.

9. Apparatus as defined in claim 8, wherein said weir means includes ahorizontal roller arranged above an upper lip portion of said vessel,said bottom sheet extending from its supply roll successively over saidroller and onto the conveyor reach of said endless belt conveyor means,whereby said bottom sheet constitutes a portion of said weir structure.

10. Apparatus as defined in claim 8, and further including a downwardlyinclined fall plate intermediate said weir means and the conveying reachof said belt conveyor means, said bottom sheet being supported by andmoving down said fall plate prior to reaching the belt conveyor. A

11. Apparatus as defined in claim 10, and further including means foradjusting the angle of inclination of said fall plate.

12. Apparatus as defined in claim 11, and further including means foradjusting the surface contour of said fall plate. 1

13. Apparatus for producing a continuous strand of polymeric foam from amixture of liquid foam reactants, comprising v a. a vessel in whichliquid foam reactants may expand upwardly; b. means for supplying liquidfoam reactants to the bottom of said vessel; 0. weir means so arrangedadjacent the upper portion of said vessel that the foam which rises byexpansion in said vessel flows over said weir means, said weir meansincluding a horizontal roller adjacent an upper lip portion of saidvessel;

(1. open-topped channel-shaped conveyor means for conveying foam awayfrom said weir structure, said conveyor means including a pair ofparallel spaced vertical side wall sheets and a bottom wall sheetarranged to define a channel configuration, each of said side and bottomwall sheets being supplied from a separate supply roll, respectively,said bottom sheet extending successively from its supply roll over saidroller and away from said weir means;

e. and means for controlling the amount of foam flowing at differentpoints along said weir means, thereby to control the top surface shapeof the expanded foam in said channel-shaped conveyor means.

14. Apparatus as defined in claim 13, wherein said foam flow controlmeans comprises a boom connected with said vessel lip portion andextending parallel with said weir means, said boom being shaped alongits length so as to produce a varying distribution of foam flow alongthe length of said boom.

15. Apparatus as defined in claim 13, wherein said foam flow controlmeans comprises an apron of sheet material attached to said vessel lipand overlying said bottom sheet, the free edge of said apron beingcontoured to produce varying degrees of restraint of foam flow acrosssaid apron.

16. Apparatus as defined in claim 8, wherein the upstream end of saidbelt conveyor is adjacent an upper lip portion of said vessel, saidbottom sheet extending from its supply roll adjacent said lip portion,around the upstream end of the belt conveyor and in supported engagementwith said belt conveyor, whereby the upstream end of the belt conveyorand the region of the bottom sheet overlying said end constitute saidweir means.

17. Apparatus as defined in claim 1, wherein said vessel comprises atrough supported within said channelshaped conveyor means with minimumclearance from the bottom sheet portion thereof, said trough includingan elevated lip portion, and a downwardly-directed fall plate portionextending from said lip portion to a position adjacent the conveyorbottom, said lip portion constituting said weir structure.

18. Apparatus as defined in claim 17, and further including an apron ofsheet material attached to said trough and extending downstream of theconveyor beneath the lower edge of said fall plate and overlying theconveyor bottom, said apron serving to restrain flow of foam from thefall plate onto the conveyor.

19. Apparatus as defined in claim 18, wherein the free edge of saidapron is contoured to produce varying degrees of restraint on foamacross said apron.

20. Apparatus as defined in claim 8, wherein said vessel has anoverhanging lip which comprises a portion of said weir means, andfurther including a horizontal roller arranged beneath and spaced fromsaid overhanging lip, said bottom sheet passing from said supply rollthrough the space between said roller and said overhanging lip and beingentrained over said roller prior to being supported by said beltconveyor.

UNITED STATES PATENT OFFICE CERTEHCATE OF 0RRECTION' Patent No. I 3, 832099 Dated August 27, 1974 Inventor(s) Laader Berg It is certified thaterror appears in the aboveidentified patent and that said Letters Patentare hereby corrected as shown below:

In the heading, the assignee's name should read:

Unifoam AG (SEAL) Attest:

GIBSON JR. C. MARSHALL DANN McCOY M.

Commissioner of Patents Attesting Officer FORM Do-1050 (m'eg) uscoMM-Dc60376-P69 U.S, GOVERNMENT PRINTING OFFICE: 1969 O356-334

1. Apparatus for producing a continuous strand of polymeric foam from amixture of liquid foam reactants, which comprises a. a vessel in whichliquid foam reactants may expand upwardly; b. means for supplying liquidfoam reactants to the bottom of said vessel; c. weir means so arrangedadjacent the upper portion of said vessel that the foam which rises byexpansion in said vessel flows over said weir means; and d. open-toppedchannel-shaped conveyor means for conveying foam away from said weirmeans.
 2. Apparatus as defined in claim 1, wherein said vessel comprisesa trough having a length dimension in a direction parallel with saidweir means which corresponds with the width of the foam strand to beproduced.
 3. Apparatus as defined in claim 2, wherein the width of saidtrough increases with trough height.
 4. Apparatus as defined in claim 1,and including at least one baffle plate arranged in the lower part ofthe trough for dividing the trough into a plurality of sections. 5.Apparatus as defined in claim 4, wherein said reactant supplying meansis operable to supply reactants separately and simultaneously to each ofsaid trough sections.
 6. Apparatus as defined in claim 1, and furtherincluding means for adjusting the horizontal cross-sectionalconfiguration of said vessel.
 7. Apparatus as defined in claim 1,wherein said conveyor means comprises a pair of parallel spaced verticalside wall sheets and a bottom wall sheet arranged to define a channelconfiguration, each of said side and bottom wall sheets being suppliedfrom a separate supply roll, respectively.
 8. Apparatus as defined inclaim 7, wherein said conveyor means further includes an endless beltconveyor the conveying reach of which moves in a direction away fromsaid vessel in supporting engagement with said bottom sheet, said bottomsheet being drawn from its supply roll upwardly past said vessel by saidbelt conveyor.
 9. Apparatus as defined in claim 8, wherein said weirmeans includes a horizontal roller arranged above an upper lip portionof said vessel, said bottom sheet extending from its supply rollsuccessively over said roller and onto the conveyor reach of saidendless belt conveyor means, whereby said bottom sheet constitutes aportion of said weir structure.
 10. Apparatus as defined in claim 8, andfurther including a downwardly inclined fall plate intermediate saidweir means and the conveying reach of said belt conveyor means, saidbottom sheet being supported by and moving down said fall plate prior toreaching the belt conveyor.
 11. Apparatus as defined in claim 10, andfurther including means for adjusting the angle of inclination of saidfall plate.
 12. Apparatus as defined in claim 11, and further includingmeans for adjusting the surface contour of said fall plate. 13.Apparatus for producing a continuous strand of polymeric foam from amixture of liquid foam reactants, comprising a. a vessel in which liquidfoam reactants may expand upwardly; b. means for supplying liquid foamreactants to the bottom of said vessel; c. weir means so arrangedadjacent the upper portion of said vessel that the foam which rises byexpansion in said vessel flows over said weir means, said weir meansincluding a horizontal roller adjacent an upper lip portion of saidvessel; d. open-topped channel-shaped conveyor means for conveying foamaway from said weir structure, said conveyor means including a pair ofparallel spaced vertical side wall sheets and a bottom wall sheetarranged to define a channel configuration, each of said side and bottomwall sheets being supplied from a separate supply roll, respectively,said bottom sheet extending successively from its supply roll over saidroller and away from said weir means; e. and means for controlling theamount of foam flowing at different points along said weir means,thereby to control the top surface shape oF the expanded foam in saidchannel-shaped conveyor means.
 14. Apparatus as defined in claim 13,wherein said foam flow control means comprises a boom connected withsaid vessel lip portion and extending parallel with said weir means,said boom being shaped along its length so as to produce a varyingdistribution of foam flow along the length of said boom.
 15. Apparatusas defined in claim 13, wherein said foam flow control means comprisesan apron of sheet material attached to said vessel lip and overlyingsaid bottom sheet, the free edge of said apron being contoured toproduce varying degrees of restraint of foam flow across said apron. 16.Apparatus as defined in claim 8, wherein the upstream end of said beltconveyor is adjacent an upper lip portion of said vessel, said bottomsheet extending from its supply roll adjacent said lip portion, aroundthe upstream end of the belt conveyor and in supported engagement withsaid belt conveyor, whereby the upstream end of the belt conveyor andthe region of the bottom sheet overlying said end constitute said weirmeans.
 17. Apparatus as defined in claim 1, wherein said vesselcomprises a trough supported within said channel-shaped conveyor meanswith minimum clearance from the bottom sheet portion thereof, saidtrough including an elevated lip portion, and a downwardly-directed fallplate portion extending from said lip portion to a position adjacent theconveyor bottom, said lip portion constituting said weir structure. 18.Apparatus as defined in claim 17, and further including an apron ofsheet material attached to said trough and extending downstream of theconveyor beneath the lower edge of said fall plate and overlying theconveyor bottom, said apron serving to restrain flow of foam from thefall plate onto the conveyor.
 19. Apparatus as defined in claim 18,wherein the free edge of said apron is contoured to produce varyingdegrees of restraint on foam across said apron.
 20. Apparatus as definedin claim 8, wherein said vessel has an overhanging lip which comprises aportion of said weir means, and further including a horizontal rollerarranged beneath and spaced from said overhanging lip, said bottom sheetpassing from said supply roll through the space between said roller andsaid overhanging lip and being entrained over said roller prior to beingsupported by said belt conveyor.